如何将先前的输入值插入文本区域？

Question

I'm new to HTML/CSS and have created a simple contact form to enter a name, number, and have a populated textarea with a short message but would like to automatically populate the name area within the text field with whatever was put into the name's input field previously in the contact form. What is the best way to do this?

<fieldset>
<h1>Contact Form</h1>
<label for="name">Patient Name:</label>
<input name="name" id="name" type="text" size="40" maxlength="100">
<label for="number">Patient Number:</label>
<input name="number" id="number" type="text" size="40" maxlength="12">
<label for="message">Text Messge:</label>
<textarea name="message" id="message" cols="40" rows="10">
Hi [name], thank you for visiting us!
</textarea>
<input class="btn" name="submit" type="submit" value="Send">
</fieldset>

Answer 1

Some JavaScript should solve your problem.

Insert this script tag into your HTML file after the form.

<script>
  // save the location of the name field
  var name_field = document.getElementById('name');

  //add an event listener to activate if the value of the field changes
  name_field.addEventListener('change', function() {
    // when the field changes run the following code

    // copy the text (value)
    var name = name_field.value;

    // concatenate it with the desired message
    var autoFill = 'Hi ' + name + ', thank you for visiting us!';

    // and paste it into the message field.
    document.getElementById('message').value = autoFill;
  })
</script>

Answer 2

For dynamic behavior you are gonna need some javascript.

<input name="number" id="number" type="text" oninput="getNumber()" size="40" maxlength="12">

 <script>
var getNumber = function() {
    document.getElementById("message").innerHTML = "Hi " + document.getElementById("name").value + ", thank you for visiting us";
}
</script>

And as it looks right now, you probably shouldn't be using a textArea to display this message, rather use a paragraph element. AngularJS is perfect for a scenario like this if you are more interested.